CN203872381U - LED and fluorescent lamp ballast compatible interface circuit - Google Patents

Abstract

The utility model relates to an LED and fluorescent lamp electronic ballast compatible interface circuit. According to the circuit, a starting capacitor of the fluorescent lamp electronic ballast is connected with a capacitor C in parallel, reactive power exchange is performed between the capacitor C and a push-pull circuit of the electronic ballast, the push-pull circuit performs constant-power control on apparent power, and then the active power must decrease under the condition that reactive power increases, so active output of the electronic ballast is adjusted through adjustments of the capacity of the capacitor C. The interface circuit designed according to the principle has the advantages of simple structure and low loss and is a first-kind interface circuit; and, furthermore, the output power of the electronic ballast can also be effectively reduced in a manner that a direct-current LED is connected into a resonance circuit of the starting capacitor in series through a rectification circuit, and the obtained circuit is a second-kind interface circuit.

Description

The interface circuit of a kind of LED and fluorescent lamp ballast compatibility

Technical field

The utility model belongs to LED lighting field, and particularly a kind of interface circuit of and fluorescent lamp ballast compatibility, is single-phase change-over circuit and the LED lamp thereof for electronic ballast for fluoresent lamp specifically.

Background technology

Enter after 21 century, it is important all the more that energy and environment seem, energy-conserving and environment-protective become people's common recognition.Current, illumination accounts for 20% left and right of world's total energy consumption, if can be low to consume energy, life-span LED long, Environmental Safety replaces the traditional lighting of current poor efficiency, high power consumption, will bring undoubtedly a global illumination revolution, and the sustainable development of China is had more to strategic importance.2004, there is short of electricity phenomenon the most serious since the nineties in last century in China, 26 the provinces and cities' power cuts to limit consumption in the whole nation, and only East China is just because power cuts to limit consumption has caused the loss that exceedes 20,000,000,000 yuans.Within 2004, China's generating total amount is 2.187 trillion kilowatt hours, wherein have again 80% for thermal power generation, a large amount of raw coal and oil burn, produce a large amount of pollutants, and as long as the words that current 1/3 incandescent lamp is replaced by LED, annual can be just that country saves electricity consumption 1,000 hundred million kilowatt hours, and this is equivalent to save the annual energy output of Three Gorges Projects.Recognize the importance of semiconductor lighting, various countries carry out semiconductor lighting plan one after another.

Light-emitting diode (LED) is as new and effective solid light source, has the remarkable advantages such as efficient, energy-saving and environmental protection, life-span length, safety, rich color, volume are little, fast response time, vibration resistance, easy care.Its appearance is acknowledged as one of 21 century high-tech sector most with prospects.Illumination application is world's second largest energy resource consumption, accounts for 19% of all energy resource consumptions.If by the alternative conventional incandescent of LED, by the power consumption of saving 90%.According to estimates, if China in 2010 has more than 1/3 incandescent lamp to be replaced by semiconductor lighting technology, electricity consumption 1,000 hundred million degree that can save lighting for a year so, save raw coal 0.5 hundred million t, reduce waste gas and dirt slag discharge capacity approximately 6,670,000 t.Estimate according to Japan, as adopted light efficiency than incandescent lamp and the fluorescent lamp of the alternative Japanese half of the LED of the taller twice of fluorescent lamp, be equivalent to can save every year 6000000000 liters of crude oil.According to doctor's JeffNelson prophesy of San Diego, USA National Laboratory, incandescent lamp and the fluorescent lamp in the whole world are all replaced by white light LEDs, will save the energy output [1] of 38 nuclear power stations.Therefore, the illumination application process of development LED industry, propelling LED, can reduce energy resource consumption and environmental pollution greatly, and the sustainable development of China is had to great strategic significance.

From the above mentioned, replace fluorescent lamp with LED and there is very large economy, environmental benefit.And consider the significant cost of rewiring, desirable replacement scenario should be not need to remove original light fixture, also in the situation that does not need the circuit of original equipment to reequip, there is scholar to propose (N.Chen and H.Chung, " A Universal Driving Technology for Retrofit LED Lamp for Fluorescent Lighting F ixtures ", Applied Power Electronics Conference and Exposition (APEC), 2012Twenty-SeventhAnnual IEEE, pp.980-987, Feb.2012) directly with LED displacement light fixture, fluorescent tube is changed.

The problem of this ideal scheme is, the Driving technique of LED and the Driving technique of fluorescent tube are different, and electric ballast is can not driven LED luminous.Therefore necessary circuit need to be in the output of electric ballast, connected, to reach the driven to LED, by this part circuit and the integrated LED displacement light fixture that manufactures of LED, just the displacement to fluorescent tube can be realized.

The U.S., Japan, Korea S, China and some European countries etc., all in the LED illumination plan of carrying out in various degree, change the outfit hundreds of millions of fluorescent lamps into LED.As the U.S. has realized 55% fluorescent lamp replacing in 2010, and higher replacement rate will be realized in future.

At present, electric ballast is can not driven LED luminous, and one of reason is under equal streams lightness, the energy consumption of LED is not as good as the half of fluorescent lamp, the design of electric ballast is to ensure that brightness of fluorescent lamp is substantially constant, i.e. constant power output can not driven LED after causing replacing; Formerly therefore two be to adopt uncontrollable circuit to change, just be difficult to reduce the power output of electric ballast, adopt current limliting or controlable electric current to change, efficiency can reduce again greatly, best way is that electric ballast reduces power output automatically, but in the case of neither removing original light fixture, being also difficult to realize the circuit of original equipment not being reequiped.

Utility model content

The purpose of this utility model is to provide a kind of in the case of not needing to remove original light fixture, the also LED not needing the circuit of original equipment to reequip and the interface circuit of fluorescent lamp ballast compatibility.

The technical solution of the utility model is as follows: the interface circuit of a kind of LED and fluorescent lamp ballast compatibility, it is characterized in that: there are two lamp holders 1 and 2, correspond respectively to two termination lamp sockets 1 and 2 of electric ballast lamp socket, lamp holder 1 inserts lamp socket 1, and two cathode contact A, a of this lamp socket 1 are drawn; In like manner, lamp holder 2 inserts lamp socket 2, and two cathode contact B, b of this lamp socket 2 are drawn; Diode D1 and D2 forward are connected as brachium pontis, and tie point is the first intermediate node, and brachium pontis two ends are DC terminal, and the first intermediate node is connected with cathode contact A, as the brachium pontis one of three-phase commutation bridge; Diode D5 and D6 forward are connected as brachium pontis, and tie point is the second intermediate node, and brachium pontis two ends are DC terminal, and the second intermediate node is connected with cathode contact a, as the brachium pontis two of three-phase commutation bridge; Diode D3 and D4 forward are connected as brachium pontis, and tie point is the 3rd intermediate node, and brachium pontis two ends are DC terminal, and by cathode contact B and b short circuit, the 3rd intermediate node is connected with b with cathode contact B, as the brachium pontis three of three-phase commutation bridge; The DC terminal parallel connection of this three-phase commutation bridge is as DC side, and as the DC power supply of LED.

A kind of in the case of not needing to remove original light fixture, the also single-phase change-over circuit that can set for the power of electronic ballast for fluoresent lamp lamp socket not needing the circuit of original equipment to reequip, it is characterized in that: there are two lamp holders, a lamp holder inserts lamp socket, and will after the cathode contact short circuit of this lamp socket, draw as one end, in like manner, another lamp holder inserts another lamp socket, after short circuit cathode contact, draw as the other end, capacitor C is in parallel with ac lighting circuit is one, and this piece is connected to formation loop, two ends.

Advantage is, four cathode contacts of electronic ballast for fluoresent lamp are converted to single-phase two contacts, and the capacitance that simultaneously changes capacitor C can change electronic ballast for fluoresent lamp and offer the power of single phase circuit; Annulus fluorescent lamp electronic ballast also has four cathode contacts of two lamp sockets, be characterized in two lamp holder positions very close to, the lamp holder position of corresponding single-phase change-over circuit also very close to, be equally applicable to annular lamp tube.

The invention of described single-phase change-over circuit is specialized, single-phase change-over circuit provides power supply for uncontrollable AC LED, obtain the adjustable LED circuit for lamp of the power for electric ballast lamp socket that the utility model provides, it is characterized in that, be one end by two cathode contact short circuits of a lamp socket of electric ballast, be the other end by two cathode contact short circuits of another lamp socket of electric ballast, capacitor C is in parallel with AC LED is one, and this piece is connected across two ends.Described AC LED is that AC LED refers to, the uncontrollable circuit being made up of LED, diode or passive filter circuit is different from direct-current LED, can work in positive half cycle and the negative half period of alternating voltage, has bilateral volt-ampere characteristic.

Advantage is, adopts uncontrollable AC LED effectively to reduce circuit loss, controls the power of AC LED by control capacittance C, reached controlled effect.

By described for the adjustable further refinement of LED circuit for lamp of the power of electric ballast lamp socket, by ACLED be divided into the pure LED lamp adjustable for the power of electric ballast lamp socket, for two kinds of the adjustable pure diode lights of the power of electric ballast lamp socket, the AC LED of described pure LED refers to, the structure of connecting after according to positive inverse parallel with direct-current LED or the pure LED circuit connecting according to the structure of rectifier bridge, and any rectification circuit that can expect or simply replace; Describedly it is characterized in that for the adjustable pure diode lights of the power of electric ballast lamp socket, diode D1 and D2 series connection become a rectifying bridge arm, and tie point is intermediate node, and brachium pontis two ends are DC terminal; Diode D3 and D4 series connection become another rectifying bridge arm, and two brachium pontis DC terminal parallel connections are as DC side, and passive low ventilating filter is in parallel with direct-current LED is one, and this piece is connected to DC side two ends; Capacitor C is connected across two intermediate nodes; A lamp holder inserts lamp socket, and will after the cathode contact short circuit of this lamp socket, draw as one end, and in like manner, another lamp holder inserts another lamp socket, draws as the other end after short circuit, and two intermediate nodes are connected in formation loop, two ends.

Described pure diode circuit should not be limited with bridge rectifier and capacitor filtering; also should comprise and partly press bridge rectifier, transformation rectification with centre tapped transformer and diode composition; or the harmonic elimination circuit of inductance, electric capacity, resistance connection in series-parallel composition; or at direct-current LED two ends reverse Schottky diode in parallel as protective circuit; or two forward and reverse series connection of Schottky diode are in parallel with direct-current LED as protective circuit, and any similar rectification circuit that can expect or simply replacement.

Advantage is: for reducing the damage of stroboscopic to human eye, there is strict regulation various countries to fluorescent lamp operation frequency, shunt capacitance C, although can regulate the power output of ballast, but change the operating frequency of ballast, do not controlled rectification interchange is converted to direct current pulse wave, then direct current pulse wave has been become to pure direct current by the low pass filter of shunt capacitance or series inductance composition, with this DC driven direct-current LED, effectively solve the problem of stroboscopic.

In addition, the utility model provide a kind of in the case of do not need to remove original light fixture, also do not need the circuit of original equipment to reequip for the three-phase commutation bridge of electric ballast the LED lamp as change-over circuit, it is characterized in that: two diodes are connected as brachium pontis, tie point is intermediate node, brachium pontis two ends are DC terminal, and intermediate contact is as a phase of rectifying bridge arm; In like manner, by D1 to D6 totally 6 three brachium pontis that diode forms between two, its DC terminal parallel connection is as DC side, and after the filtering of DC side access passive low ventilating filter, as the DC power supply of LED, intermediate contact is as the three-phase of three brachium pontis rectifier bridges; Negative electrode A and a, respectively as two-phase, as another phase, amount to three-phase after negative electrode B and b short circuit, are connected one to one with the three-phase of three brachium pontis rectifier bridges.

The advantage of this circuit is not under the condition of series resistive element, the power output of electric ballast to be reduced to approximately 50% in loop.Rectification principle accordingly can also obtain the LED lamp of transformation rectification, divides and has according to the transformation type adopting: self coupling becomes and common transformer, divides and has: single transformation and dual transformer according to the number that adopts transformer.Adopt the LED lamp of transformation rectification as described below.

What a kind of pair of self coupling of confession of the present utility model became partly presses the LED lamp of bridge rectifier as change-over circuit, it is characterized in that: diode D1 and D2 differential concatenation are as brachium pontis, tie point is as the positive pole of DC terminal, brachium pontis two ends are connected to transformer T1 two ends, and transformer T1 centre cap is as the negative pole of DC terminal; In like manner, transformer T2 is connected with diode D5, D6; Two diode D3, D4 connect as brachium pontis, and tie point is intermediate node, and brachium pontis two ends are DC terminal, and intermediate contact is connected with two contact B or the b of negative electrode 2 as one of rectifying bridge arm, contact B and b short circuit; Three DC terminal parallel connections are as DC side, after the filter capacitor C2 of direct-current LED and low pass filter is in parallel, access DC side.What the described pair of self coupling became partly presses bridge rectifier should not become and partly press bridge rectifier to be limited with self coupling as the LED lamp of change-over circuit, adopts the rectification of full-bridge type rectification circuit after also should comprising common transformer transformation.

Feature is: as compared with the LED lamp of change-over circuit, DC side output voltage reduces half with three-phase commutation bridge.

What a kind of single self coupling of confession of the present utility model became partly presses the LED lamp of bridge rectifier as change-over circuit, it is characterized in that, what become with two self couplings partly presses bridge rectifier as compared with the LED lamp of change-over circuit, difference is, transformer T2 and diode D5, D6 are removed, only used a transformer T1, T1 is connected across contact A and a two ends of negative electrode 1.

Advantage is: what become with two self couplings partly presses bridge rectifier as compared with the LED lamp of change-over circuit, has reduced by one and half voltage rectifiers.

The utility model provide a kind of with centre tapped transformation rectifier bridge the LED lamp as change-over circuit, it is characterized in that, what become with single self coupling partly presses bridge rectifier as compared with the LED lamp of change-over circuit, difference is, self coupling becomes on T1 and has increased former limit winding, and self coupling change T1 is no longer connected across contact A and a two ends of negative electrode 1, and former limit winding and self coupling become T1 and form new transformer, and the former end bay of new transformer is connected on contact A and a two ends of negative electrode 1.

Feature is that DC side output voltage can change according to former secondary winding ratio.

The advantage of the compatibility interface circuit of above-mentioned various LED and electronic ballast for fluoresent lamp is, reduce and even regulate the power output of electric ballast simply and effectively, simultaneously usefulness substantially constant (in the case of do not need to remove original light fixture, also do not need the circuit of original equipment to reequip).

Brief description of the drawings

Fig. 1 is the single-phase change-over circuit figure that a kind of power for electronic ballast for fluoresent lamp lamp socket that the utility model provides can be set.

Fig. 2 be the utility model provide a kind of for the adjustable LED circuit for lamp figure of the power of electric ballast lamp socket.

Fig. 3 is the adjustable pure LED circuit for lamp figure of the power for electric ballast that the utility model provides.

Current characteristics curve chart when Figure 41 is the topological AC LED of the spiral of 30 LED different capacitance electric capacity in parallel.

Voltage characteristic curve when Figure 42 is the topological AC LED of the spiral of 30 LED different capacitance electric capacity in parallel.

Figure 51 is that C=10nF two goes here and there LED single-string LED current waveform figure when in parallel.

Figure 52 is that C=10nF two goes here and there LED single-string LED voltage oscillogram when in parallel.

Fig. 6 is a kind of pure diode lights circuit diagram for electric ballast that the utility model provides.

Fig. 7 is the LED circuit for lamp figure of a kind of three-phase commutation bridge for electric ballast of providing of the utility model as change-over circuit.

Fig. 8 be a kind of two self couplings for electric ballast that the utility model provides become partly press the LED circuit for lamp figure of bridge rectifier as change-over circuit.

Fig. 9 be a kind of single self coupling for electric ballast that the utility model provides become partly press the LED circuit for lamp figure of bridge rectifier as change-over circuit.

Figure 10 is a kind of LED circuit for lamp figure as change-over circuit with centre tapped transformation rectifier bridge for electric ballast that the utility model provides.

Embodiment

The utility model provides the interface of a kind of LED and fluorescent lamp ballast compatibility, this interface is the very simple circuit of a class, in the case of do not need to remove original light fixture, also do not need the circuit of original equipment to reequip effectively reduction even regulate the power output of electric ballast to adapt to the low-power consumption of LED, and usefulness is substantially constant.

The single-phase change-over circuit that embodiment 1 power can be set

Fig. 1 is the single-phase change-over circuit figure that the power for electronic ballast for fluoresent lamp lamp socket that the utility model provides can be set

In Fig. 1, capacitor C 1 is ballast build-up of luminance electric capacity, is the push-pull circuit of electric ballast in dotted line frame, and output voltage is es, and output current is is; There are respectively two lamp sockets at fluorescent lamp holder two ends, in each lamp socket, have negative electrode, comprise two contacts, and establishing a lamp socket is negative electrode 1, and two contact is A and a, is negative electrode 2 on another lamp socket, and two contact is B and b; It in chain-dotted line, is single-phase change-over circuit, it is characterized in that: there are two lamp holders, a lamp holder inserts lamp socket, and will after the cathode contact short circuit of this lamp socket, draw as one end, in like manner, another lamp holder inserts another lamp socket, draws as the other end after short circuit, capacitor C is in parallel with ac lighting circuit is one, and this piece is connected to formation loop, two ends.

Its advantage is that four cathode contacts of electronic ballast for fluoresent lamp are converted to single-phase two contacts, and the capacitance that simultaneously changes capacitor C can change electronic ballast for fluoresent lamp and offer the power of single phase circuit; Annulus fluorescent lamp electronic ballast also has four cathode contacts of two lamp sockets, be characterized in two lamp holder positions very close to, the lamp holder position of corresponding single-phase change-over circuit also very close to, be equally applicable to annular lamp tube.

AC LED is specialized-adopted to the single-phase change-over circuit of embodiment 2 is AC LED

Fig. 2 is the adjustable LED circuit for lamp figure of the power for electric ballast lamp socket that the utility model provides, and in Fig. 2, capacitor C 1 is ballast build-up of luminance electric capacity, is the push-pull circuit of electric ballast in dotted line frame, and output voltage is es, and output current is is; There are respectively two lamp sockets at fluorescent lamp holder two ends, in each lamp socket, have negative electrode, comprise two contacts, and two contacts of the negative electrode 1 on a lamp socket are A and a, and two contacts of the negative electrode 2 on another lamp socket are B and b.The pure LED lamp that the power for electric ballast lamp socket that the utility model provides can be set, it is characterized in that: be one end by the contact A of electric ballast negative electrode 1 and a short circuit, be the other end by the contact B of electric ballast negative electrode 2 and b short circuit, capacitor C is in parallel with AC LED is one, and this piece is connected across two ends.

The feature of this circuit is, by changing the capacity of capacitor C, can set or regulate push-pull circuit to be input to the power of ACLED circuit.

Described AC LED is the uncontrollable circuit that AC LED is made up of LED, diode or passive filter circuit, different from direct-current LED, can work in positive half cycle and the negative half period of alternating voltage, has bilateral volt-ampere characteristic.

Fig. 3 is the adjustable pure LED circuit for lamp figure of the power for electric ballast that the utility model provides.Fig. 3 is further specializing of circuit shown in Fig. 2, be from the different of Fig. 2: adopt spiral topology as AC LED circuit structure (applicant: Liu Xiaobo, denomination of invention: spiral topology and matrix rectifier structure thereof, application number: 201210522576.5).

Figure 41 and Figure 42 are electric current and the voltage responses that adopts circuit AC LED in the time that capacitor C is different capacitance shown in Fig. 3.In Figure 41 and Figure 42, the capacitance that transverse axis x is capacitor C, unit is nanofarad, and the longitudinal axis is the curtage value of AC LED, and unit is milliampere or volt; In enforcement, adopt the spiral being made up of 30 LED to open up the LED as AC, push-pull circuit is the electric ballast that drives specified 38W fluorescent lamp, and C1 is 3300pF.When capacitor C capacitance is at 0～10nf time, AC LED electric current and voltage increase with capacitance, and electric current maximum reaches about 350mA, and voltage maximum is about 95V; Capacitance is in 10～45nf, and AC LED electric current and voltage increase and reduce with electric capacity.

So the pure LED lamp that the power for electric ballast lamp socket that the utility model provides is adjustable, only, by changing the capacity of capacitor C, just can set or regulate circuit of electronic ballast to be input to the power of AC LED circuit; If capacitor C is tunable capacitor, just can in the time of operation, regulate the power of LED lamp, if capacitor C is definite value electric capacity, can be by selecting suitable capacitance that LED is moved under the power of setting; In addition this modulated structure is simple, and due to without current-limiting resistance, efficiency is higher.

Figure 51 is that C=10nF two goes here and there LED single-string LED current waveform figure when in parallel, and Figure 52 is that C=10nF two goes here and there LED single-string LED voltage oscillogram time in parallel.In enforcement, when C=10nf, current maxima exceedes 300mA.So, forming single string by 30 LED by spiral topology, single string rated current 160mA, adopts two series-parallel structures of list.In Figure 51, the amplitude of electric current fluctuates near 160mA taking 10ms as the cycle, and this is due to the DC voltage of push-pull circuit non-constant direct current 300V, but has the direct voltage of certain ripple, and its line wave frequency is the power frequency of 2 times just.So drawn two curves of maximum effective value and minimum effective value in Figure 41 and Figure 42, respectively corresponding ripple crest and trough moment.

Fig. 6 is the pure diode lights circuit diagram that the utility model provides.For reducing the damage of stroboscopic to human eye, there is strict regulation various countries to fluorescent lamp operation frequency.Shunt capacitance C, although can regulate the power output of ballast, has changed the operating frequency of ballast; Adopt current rectifying and wave filtering circuit to drive the AC LED of direct-current LED as light source so the utility model provides, it is characterized in that: diode D1 and D2 series connection have become a rectifying bridge arm, and tie point is intermediate node, and brachium pontis two ends are DC terminal; Diode D3 and D4 series connection become another rectifying bridge arm, and two brachium pontis DC terminal parallel connections are as DC side, and capacitor C 2 is in parallel with direct-current LED as low pass filter is one, and this piece is connected to DC side two ends; Capacitor C is connected across two intermediate nodes; A lamp holder inserts lamp socket, and will after the cathode contact short circuit of this lamp socket, draw as one end, and in like manner, another lamp holder inserts another lamp socket, draws as the other end after short circuit, and two intermediate nodes are connected in formation loop, two ends.

The AC LED that is not both of Fig. 6 and Fig. 3 has adopted current rectifying and wave filtering circuit to drive the structure of direct-current LED, so way is converted to direct current pulse wave by not controlling rectification by interchange, again direct current pulse wave is become to pure direct current by the low pass filter of shunt capacitance or series inductance composition, with this DC driven direct-current LED, effectively solve the problem of stroboscopic.

Described current rectifying and wave filtering circuit should not be limited with bridge rectifier in Fig. 6 and capacitor filtering; also should comprise half repoussage stream, transformation rectification with centre tapped transformer and diode composition; or the harmonic elimination circuit of inductance, electric capacity, resistance connection in series-parallel composition; or at direct-current LED two ends reverse Schottky diode in parallel as protective circuit; or two forward and reverse series connection of Schottky diode are in parallel with direct-current LED as protective circuit, and any similar circuit that can expect or simply replacement.

The nonadjustable single-phase change-over circuit of embodiment 3 power

Fig. 7 is the LED circuit for lamp figure of three-phase commutation bridge as change-over circuit, and in Fig. 7, capacitor C 1 is ballast build-up of luminance electric capacity, is the push-pull circuit of electric ballast in dotted line frame, and output voltage is es, and output current is is; There are respectively two lamp sockets at fluorescent lamp holder two ends, in each lamp socket, have negative electrode, comprise two contacts, and two contacts of the negative electrode 1 on a lamp socket are A and a, and two contacts of the negative electrode 2 on another lamp socket are B and b; A kind of three-phase commutation bridge for electric ballast that the utility model provides, as the LED circuit for lamp of change-over circuit, is characterized in that:

Two diodes are connected as brachium pontis, and tie point is intermediate node, and brachium pontis two ends are DC terminal, and intermediate contact is as a phase of rectifying bridge arm.In like manner, by D1 to D6 totally 6 three brachium pontis that diode forms between two, its DC terminal parallel connection is as DC side, and DC side is by the DC power supply as LED after low-pass filtering, and intermediate contact is as the three-phase of three brachium pontis rectifier bridges; Negative electrode A and a, respectively as two-phase, as another phase, amount to three-phase after negative electrode B and b short circuit, are connected one to one with the three-phase of three brachium pontis rectifier bridges.

The feature of this circuit is not under the condition of series resistive element, the power output of push-pull circuit to be reduced to approximately 50% in loop, is applicable to the low-power consumption of LED.

Fig. 8 be two self couplings become partly press bridge rectifier as the LED circuit for lamp figure of change-over circuit-

In Fig. 8, diode D1 and D2 differential concatenation are as brachium pontis, and tie point is the positive pole as DC terminal, and brachium pontis two ends are connected to transformer T1 two ends, and transformer T1 centre cap is as the negative pole of DC terminal; In like manner, transformer T2 is connected with diode D5, D6; Two diode D3, D4 connect as brachium pontis, and tie point is intermediate node, and brachium pontis two ends are DC terminal, and intermediate contact is connected with two contact B or the b of negative electrode 2 as one of rectifying bridge arm, contact B and b short circuit; Three DC terminal parallel connections are as DC side, after the filter capacitor C2 of direct-current LED and low pass filter is in parallel, access DC side.With not being both of circuit shown in Fig. 7, DC side output voltage reduces half.

Fig. 9 be single self coupling become partly press the LED circuit for lamp figure of bridge rectifier as change-over circuit.In Fig. 9, with not being both of circuit shown in Fig. 8, removed transformer T2 and diode D5, D6, only used a transformer T1, T1 is connected across contact A and a two ends of negative electrode 1, thereby has reduced by one and half voltage rectifiers.

Figure 10 is the LED circuit for lamp figure as change-over circuit with centre tapped transformation rectifier bridge.In Figure 10, with not being both of circuit shown in Fig. 9, former self coupling becomes the upper former limit winding that increases of T1, former self coupling becomes T1 and becomes secondary winding, and the contact A and a two ends that are no longer connected across negative electrode 1, former limit and secondary form new transformer, and the former end bay of new transformer is connected on contact A and a two ends of negative electrode 1.Feature is that DC side output voltage can change according to former secondary winding ratio.

The above; it is only preferably embodiment of the utility model; but protection range of the present utility model is not limited to this; any be familiar with those skilled in the art the utility model disclose technical scope in; the variation that can expect easily or replacement, within all should being encompassed in protection range of the present utility model.Therefore, protection range of the present utility model should be as the criterion with the protection range of claim.

Claims (1)

1. the interface circuit of a LED and fluorescent lamp ballast compatibility, it is characterized in that: there are two lamp holders 1 and 2, two the termination lamp sockets 1 and 2 that correspond respectively to electric ballast lamp socket, lamp holder 1 inserts lamp socket 1, and two cathode contact A, a of this lamp socket 1 are drawn; In like manner, lamp holder 2 inserts lamp socket 2, and two cathode contact B, b of this lamp socket 2 are drawn; Diode D1 and D2 forward are connected as brachium pontis, and tie point is the first intermediate node, and brachium pontis two ends are DC terminal, and the first intermediate node is connected with cathode contact A, as the brachium pontis one of three-phase commutation bridge; Diode D5 and D6 forward are connected as brachium pontis, and tie point is the second intermediate node, and brachium pontis two ends are DC terminal, and the second intermediate node is connected with cathode contact a, as the brachium pontis two of three-phase commutation bridge; Diode D3 and D4 forward are connected as brachium pontis, and tie point is the 3rd intermediate node, and brachium pontis two ends are DC terminal, and by cathode contact B and b short circuit, the 3rd intermediate node is connected with b with cathode contact B, as the brachium pontis three of three-phase commutation bridge; The DC terminal parallel connection of this three-phase commutation bridge is as DC side, and as the DC power supply of LED.